This invention relates to three-dimensional visualization, more commonly known under the name of relief photography.
Relief photography devices which use lenticular gratings or "chequerings" have already been proposed, particularly, and a long time ago, by Maurice Bonnet. This is a thoroughly perfected technique and it provides impressive results. The photograph may either be taken using special apparatus incorporating a lenticular grating from the time when the photograph is taken (direct method), or by the composition of a series of flat conventional images of the same object, produced at slightly different photographing angles (indirect method). This second method which is very interesting for scientific observation is fairly time consuming, because it almost necessarily involves a specific stage of photographic treatment which is at the same time lengthy, delicate and quite expensive.
However, for a certain number of uses, it would be necessary to rapidly have a composite image at one's disposal, almost in real time. This is notably the case in electron microscopy.